Search

Freshwater ecosystems are responsible for a large proportion of global methane emissions to the atmosphere. The radiocarbon (14C) content of this aquatic methane is useful for determining the age and source of this important greenhouse gas. Several methods already exist for the collection of aquatic methane for radiocarbon analysis, but they tend to only sample over short periods of time, which can make them unsuitable for characterizing aquatic methane over longer timespans, and vulnerable to missing short-term events. Here, we describe a new time-integrated method for the collection of aquatic methane that provides samples suitable for radiocarbon analysis, that are representative for periods of up to at least 16 days. We report the results of a suite of tests undertaken to verify the reliability of the method, and the 14C age of aquatic methane from field trials undertaken at sites within Scotland, UK. We believe that this new method provides researchers with a simple approach that is easily deployable and can be used to collect representative time-integrated samples of methane for radiocarbon analysis from a wide range of aquatic environments. [ABSTRACT FROM AUTHOR]

• Reuse of oil and gas infrastructure could reduce the running costs of a carbon storage site. • Such a scheme would be far less costly than decommissioning and would help overcome the high costs of building a carbon storage site from scratch. • As the scheme dissolves CO 2 in brine before disposal, it is a secure way to ensure no leakage with the potential for monetizing the disposal of outside sources of CO 2. Co-production of methane and geothermal energy from produced subsurface brines with onsite power generation and carbon capture has been proposed as a technically feasible means to reduce the costs of offshore carbon storage sites. In such a facility, methane is degassed from produced brine, this brine is then cooled allowing the extraction of heat and then CO 2 is dissolved into it for reinjection into a porous rock formation. Once injected into the porous reservoir formation, this CO 2 -loaded brine will sink due to its relatively higher density, providing secure storage. Here, for the first time, we investigate, the economic feasibility and energy balance of such a system within the UK North Sea. We examine the suitability of a depleted hydrocarbon field coupled with a saline formation located in the Inner Moray Firth, Scotland. We find that such a system would be highly likely to have a positive energy balance, and would be an order of magnitude cheaper that decommissioning. Furthermore, as only 10% of the site's storage capacity is needed for disposal of the CO 2 emissions associated with its operation, there is significant potential for additional revenue creation from storing CO 2 from other sources. Whilst the chosen case study site was not ideal, due to its relatively shallow depth, and hence lower than ideal heat potential, it demonstrates that reuse of redundant oil & gas infrastructure that would otherwise be decommissioned could help to offset some of the financial barriers to developing a carbon storage industry in the UK North Sea. [ABSTRACT FROM AUTHOR]